Three-Dimensional Object Printing Apparatus And Three-Dimensional Object Printing Method

Abstract

A three-dimensional object printing apparatus includes a head unit and a robot. The head unit includes a head and an energy emission unit. The head has an ejecting surface on which a nozzle is provided. The head is configured to eject ink from the nozzle toward a three-dimensional workpiece. The energy emission unit has an emitting surface from which energy for curing the ink is emitted. The robot changes relative position and relative orientation of the workpiece and the head unit. When a direction in which the head ejects the ink is defined as an ejecting direction, the ejecting surface is located closer to an ejecting direction side, which is a side toward which the ejecting direction goes, than the emitting surface is.

What is claimed is: 
     
         1 . A three-dimensional object printing apparatus, comprising:
 a head unit that includes a head and a curing unit, the head having an ejecting surface on which a nozzle is provided, the head being configured to eject liquid from the nozzle toward a three-dimensional workpiece, the curing unit having an emitting surface from which energy for curing the liquid is emitted; and   a movement mechanism that changes relative position and relative orientation of the workpiece and the head unit; wherein   when a direction in which the head ejects the liquid is defined as an ejecting direction, the ejecting surface is located closer to an ejecting direction side, which is a side toward which the ejecting direction goes, than the emitting surface is.   
     
     
         2 . The three-dimensional object printing apparatus according to  claim 1 , wherein
 a positional relationship between the ejecting surface and the emitting surface is fixed in the head unit.   
     
     
         3 . The three-dimensional object printing apparatus according to  claim 1 , wherein
 a plurality of nozzles is provided along a nozzle-row axis on the ejecting surface,   the movement mechanism includes a plurality of rotation axes that includes at least one rotation axis orientable to be parallel to the nozzle-row axis,   among the at least one rotation axis orientable to be parallel to the nozzle-row axis, one rotation axis is closest to the head unit is defined as a center rotation axis, and   in a state in which the center rotation axis and the nozzle-row axis are parallel to each other, the emitting surface is located inside a virtual circle having a center at the center rotation axis and having a radius equal to R, where R is defined as a distance between the center rotation axis and an edge of the ejecting surface that is most distant from the center rotation axis when the head is viewed in a direction of the nozzle-row axis.   
     
     
         4 . The three-dimensional object printing apparatus according to  claim 1 , wherein
 the head unit further includes a distance measurement unit that has a measuring surface for measuring a relative distance to the workpiece, and   the ejecting surface is located closer to the ejecting direction side than the measuring surface is.   
     
     
         5 . A three-dimensional object printing apparatus, comprising:
 a head unit that includes a head and a distance measurement unit, the head having an ejecting surface on which a nozzle is provided, the head being configured to eject liquid from the nozzle toward a three-dimensional workpiece, the distance measurement unit having a measuring surface for measuring a relative distance to the workpiece; and   a movement mechanism that changes relative position and relative orientation of the workpiece and the head unit; wherein   when a direction in which the head ejects the liquid is defined as an ejecting direction, the ejecting surface is located closer to an ejecting direction side, which is a side toward which the ejecting direction goes, than the measuring surface is.   
     
     
         6 . The three-dimensional object printing apparatus according to  claim 5 , wherein
 a positional relationship between the ejecting surface and the measuring surface is fixed in the head unit.   
     
     
         7 . The three-dimensional object printing apparatus according to  claim 5 , wherein
 a plurality of nozzles is provided along a nozzle-row axis on the ejecting surface,   the movement mechanism includes a plurality of rotation axes that includes at least one rotation axis orientable to be parallel to the nozzle-row axis,   among the at least one rotation axis orientable to be parallel to the nozzle-row axis, one rotation axis is closest to the head unit is defined as a center rotation axis, and in a state in which the center rotation axis and the nozzle-row axis are parallel to each other, the measuring surface is located inside a virtual circle having a center at the center rotation axis and having a radius equal to R, where R is defined as a distance between the center rotation axis and an edge of the ejecting surface that is most distant from the center rotation axis when the head is viewed in a direction of the nozzle-row axis.   
     
     
         8 . The three-dimensional object printing apparatus according to  claim 5 , wherein
 the head unit further includes a curing unit that has an emitting surface from which energy for curing the liquid is emitted, and   the ejecting surface is located closer to the ejecting direction side than the emitting surface is.   
     
     
         9 . The three-dimensional object printing apparatus according to  claim 4 , wherein
 the emitting surface is located between the measuring surface and the ejecting surface in the ejecting direction.   
     
     
         10 . The three-dimensional object printing apparatus according to  claim 4 , wherein
 a distance between the emitting surface and the ejecting surface in the ejecting direction is shorter than a distance between the measuring surface and the ejecting surface in the ejecting direction.   
     
     
         11 . The three-dimensional object printing apparatus according to  claim 4 , wherein
 a plurality of nozzles is provided along a nozzle-row axis on the ejecting surface, and   in a direction orthogonal to both the nozzle-row axis and the ejecting direction, the ejecting surface is located between the emitting surface and the measuring surface.   
     
     
         12 . The three-dimensional object printing apparatus according to  claim 4 , wherein
 when the head unit is viewed from the ejecting direction side, at least a part of a flow passage through which the liquid is supplied to the head is located between the distance measurement unit and the curing unit, and   the distance measurement unit and the curing unit generate heat when driven.   
     
     
         13 . The three-dimensional object printing apparatus according to  claim 1 , wherein
 a plurality of nozzles is provided along a nozzle-row axis on the ejecting surface, and   in a direction orthogonal to both the nozzle-row axis and the ejecting direction, a width of the ejecting surface is less than a width of the emitting surface.   
     
     
         14 . The three-dimensional object printing apparatus according to  claim 1 , wherein
 the emitting surface is inclined away from a position of the head.   
     
     
         15 . The three-dimensional object printing apparatus according to  claim 1 , wherein
 a plurality of nozzles is provided along a nozzle-row axis on the ejecting surface, and   on at least one side of a direction along the nozzle-row axis, an edge of the emitting surface is not beyond an edge of the ejecting surface.   
     
     
         16 . The three-dimensional object printing apparatus according to  claim 5 , wherein
 a plurality of nozzles is provided along a nozzle-row axis on the ejecting surface, and   on at least one side of a direction along the nozzle-row axis, an edge of the measuring surface is not beyond an edge of the ejecting surface.   
     
     
         17 . The three-dimensional object printing apparatus according to  claim 1 , wherein the movement mechanism is an articulated robot that has a plurality of joints. 
     
     
         18 . A three-dimensional object printing method for performing printing on a print target area of a workpiece by using a head unit, the head unit including a head and a curing unit, the head having an ejecting surface on which a nozzle is provided, the head being configured to eject liquid from the nozzle toward the workpiece that is three dimensional, the curing unit having an emitting surface from which energy for curing the liquid is emitted, wherein
 when a direction in which the head ejects the liquid is defined as an ejecting direction, the ejecting surface is located closer to an ejecting direction side, which is a side toward which the ejecting direction goes, than the emitting surface is,   the workpiece has, at a position different from the print target area, a protruding portion that protrudes toward a side where the head unit is located, and   when the liquid is ejected from the head with the ejecting surface facing the print target area, the emitting surface overlaps with the protruding portion as viewed in the ejecting direction.   
     
     
         19 . The three-dimensional object printing method according to  claim 18 , wherein
 when the liquid is ejected from the head with the ejecting surface facing the print target area, at least a part of the protruding portion is located between the ejecting surface and the emitting surface in the ejecting direction.